It depends from your current iCloud configuration and what other devices you have in your possession.

If you have activated iCloud Photo Library, then your photos & videos are automatically copied to iCloud. If you have activated the “Optimize iPhone Storage” option, then you do not have the full resolution version of your photos and videos locally stored on your iPhone anymore.

Dan Rothbart asked this question on Quora and added the following information:

Yes, #firstworldproblems, I know. My wife and I are both tech savvy, and take too many iPhone pictures and video of our two children. We each have a MacBook with a full internal hard disk, and external storage. She is the better photo organizer. I use clips to make home movies.

With the recent releases of Family Sharing, Apple Photos, and iCloud Photo Library, I see an opportunity to reduce our storage cost/complexity, and to let us each take advantage of the other's creative & organizational skills.